Display device

Abstract

A display device with improved light-emitting efficiency is disclosed. The display device includes a plurality of pixels, a light emitting device provided in each of the pixels, the light emitting device having first and second surfaces which are opposite to each other, first and second electrodes electrically and respectively connected to the first and second surfaces of the light emitting device, and a metal oxide pattern interposed between the second surface of the light emitting device and the second electrode. The metal oxide pattern includes first and second regions. The first region encloses the second region, and the second region has a contact hole exposing at least a portion of the second surface. The second electrode is coupled to the second surface through the contact hole, and the first and second regions have crystalline phases different from each other.

What is claimed is: 
     
       1. A display device, comprising:
 a plurality of pixels; 
 a light emitting device provided in each of the plurality of pixels, the light emitting device having a first surface and a second surface, which are opposite to each other; 
 a first electrode electrically connected to the first surface of the light emitting device; 
 a second electrode electrically connected to the second surface of the light emitting device; and 
 a metal oxide pattern interposed between the second surface of the light emitting device and the second electrode, 
 wherein the metal oxide pattern comprises a first region and a second region, 
 the first region encloses the second region, 
 the second region has a contact hole exposing at least a portion of the second surface, 
 the second electrode is coupled to the second surface through the contact hole, and 
 the first region and the second region have crystalline phases different from each other. 
 
     
     
       2. The display device of  claim 1 , wherein a density of the first region is higher than a density of the second region. 
     
     
       3. The display device of  claim 1 , wherein a crystallization temperature of the first region is higher than a crystallization temperature of the second region. 
     
     
       4. The display device of  claim 1 , wherein the first region comprises alumina of single crystalline α-phase, and
 the second region comprises alumina of polycrystalline γ-phase. 
 
     
     
       5. The display device of  claim 1 , wherein the first surface comprises a third region and a fourth region, which are edge and center regions thereof, and
 a density of threading dislocations in the third region is higher than a density of threading dislocations in the fourth region. 
 
     
     
       6. The display device of  claim 1 , wherein the light emitting device further comprises a sidewall, which is extended from the first surface to the second surface, and
 the sidewall comprises a {n −n 0 k} facet, where each of indices n and k is an integer of 1 or greater. 
 
     
     
       7. The display device of  claim 6 , wherein the light emitting device has a hexagonal shape, when viewed in a plan view,
 the sidewall comprises first to sixth facets, and 
 the first to sixth facets are arranged along sides of the light emitting device defining the hexagonal shape. 
 
     
     
       8. The display device of  claim 1 , wherein an area of the second surface is larger than an area of the first surface. 
     
     
       9. The display device of  claim 1 , wherein the light emitting device comprises a first semiconductor layer of p-type, an active layer, and a second semiconductor layer of n-type, which are sequentially stacked,
 the first semiconductor layer is adjacent to the first surface, and 
 the second semiconductor layer is adjacent to the second surface. 
 
     
     
       10. The display device of  claim 1 , wherein the light emitting device comprises at least one of GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, or combinations thereof. 
     
     
       11. A display device, comprising:
 a plurality of pixels; and 
 a light emitting device provided in each of the plurality of pixels, 
 wherein the light emitting device comprises a first surface and a second surface, which are opposite to each other, 
 the light emitting device comprises a first semiconductor layer of p-type, an active layer, and a second semiconductor layer of n-type, which are sequentially stacked, 
 the first semiconductor layer is adjacent to the first surface, 
 the second semiconductor layer is adjacent to the second surface, 
 the first surface comprises a first region and a second region, which are edge and center regions thereof, 
 the first surface has a first width, 
 the second region has a second width, 
 a ratio of the second width to the first width ranges from 0.7 to 0.9, and 
 a density of threading dislocations is higher in the first region than in the second region. 
 
     
     
       12. The display device of  claim 11 , further comprising a metal oxide pattern covering the second surface of the light emitting device,
 wherein the metal oxide pattern comprises a third region and a fourth region, which are edge and center regions thereof, 
 the fourth region has a contact hole exposing at least a portion of the second surface, and 
 the third region and the fourth region have crystalline phases different from each other. 
 
     
     
       13. The display device of  claim 12 , wherein the second region and the fourth region are vertically overlapped with each other. 
     
     
       14. The display device of  claim 11 , wherein a density of threading dislocations in the first surface ranges from 3×106/cm2 to 3×108/cm2. 
     
     
       15. The display device of  claim 11 , wherein the light emitting device further comprises a sidewall, which is extended from the first surface to the second surface, and
 the sidewall comprises a {n −n 0 k} facet, where each of indices n and k is an integer of 1 or greater. 
 
     
     
       16. The display device of  claim 11 , further comprising a metal oxide pattern covering the second surface of the light emitting device,
 wherein the metal oxide pattern comprises a third region and a fourth region, which are edge and center regions thereof, and 
 the fourth region has a contact hole exposing at least a portion of the second surface. 
 
     
     
       17. A light emitting device comprising:
 a first semiconductor layer; 
 an active layer provided on the first semiconductor layer; 
 a second semiconductor layer provided on the active layer; and 
 a metal oxide pattern provided on the second semiconductor layer; 
 wherein the first semiconductor layer is adjacent to a first surface of the light emitting device, the second semiconductor layer is adjacent to a second surface of the light emitting device, and the first surface and the second surface face each other, 
 wherein the metal oxide pattern comprises a first region and a second region, 
 wherein the first region surrounds the second region, and 
 wherein the first region and the second region have different crystal phases. 
 
     
     
       18. The light emitting device of  claim 17 , wherein a density of the first region is higher than a density of the second region. 
     
     
       19. The light emitting device of  claim 17 , wherein the second region has a contact hole exposing at least a portion of the second surface. 
     
     
       20. The light emitting device of  claim 17 , wherein the first region comprises alumina of single crystalline α-phase, and
 wherein the second region comprises alumina of polycrystalline γ-phase. 
 
     
     
       21. The light emitting device of  claim 17 , wherein the first surface comprises a third region and a fourth region, which are edge and center regions thereof, and
 wherein a density of threading dislocations in the third region is higher than a density of threading dislocations in the fourth region. 
 
     
     
       22. The light emitting device of  claim 17 , wherein the light emitting device further comprises a sidewall, which is extended from the first surface to the second surface, and
 wherein the sidewall comprises a {n −n 0 k} facet, where each of indices n and k is an integer of 1 or greater. 
 
     
     
       23. The light emitting device of  claim 22 , wherein the light emitting device has a hexagonal shape, when viewed in a plan view,
 wherein the sidewall comprises first to sixth facets, and 
 wherein the first to sixth facets are arranged along sides of the light emitting device defining the hexagonal shape. 
 
     
     
       24. The light emitting device of  claim 17 , wherein an area of the second surface is larger than an area of the first surface. 
     
     
       25. The light emitting device of  claim 17  wherein the first semiconductor layer is a P-type semiconductor layer, and the second semiconductor layer is an N-type semiconductor layer. 
     
     
       26. The light emitting device of  claim 17 , wherein the light emitting device includes at least one of GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, and combination of thereof.